>>Well, in the TV series, several Mental Models survived the sinking of >>their ship parts without any evident ill effects, other than being put >>out that they'd lost most of their firepower.>>Was that just sinking, as in >mostly-intact-but-full-of-water-and-not-floating, or as happened to >Iona, abruptly reduced to a pile of inactive nanomaterial?

Oh, yeah, sorry - sinking as in destruction, not actual submergence. Haruna and Kirishima, for instance, ended up as big drifts of silver sand on a beach near Yokosuka, while Haruna turned up on the other side of a Haruna-shaped hole in a warehouse wall several miles away with Kirishima's Union Core in her pocket. Since their propulsion systems are gravity-manipulation-based, most Fog ships are, in fact, submersible, even if they don't represent ships that were in real life (Takao, for instance, lurks around submerged while her Mental Model goes book shopping at one point).